This invention relates to a pulse tube refrigerator (PTR) system that includes an arrangement for suppressing noise and vibrations.
Refrigeration systems used with magnetic resonance imaging (MRI) and other medical applications work by expanding high pressure helium gas, supplied from a compressor through a first gas transfer line to a regenerator device where the gas expands. This expanded gas now at lower pressure and higher velocity than the supplied high pressure gas, is returned to the compressor through a second gas transfer line. To operate at the required temperatures and pressures, these lines tend to be made of corrugated stainless steel. The increased velocity of the returning gas passing through the line leads to noise and vibration in the cooling system. Generally, in medical applications, the PTR and three quarters of the gas transfer line is installed in the examination room which for MRI is an RF cabin and also an anechoic chamber, as a result of which the impact of the noise is negligible, so no steps are taken to reduce noise and vibration caused by the return flow. However, as future applications for PTR's are developed where there would not otherwise be a requirement for an anechoic room, then this could significantly increase the expense of installing the system and it may require more space than is practical for the user to provide.